Resilient Seal

ABSTRACT

The present invention is directed to a resilient, annular, seal. The annular seal has a generally “J” shaped or hook-shaped cross-section ( 50 ). The annular seal includes a first end portion ( 52 ) having a first distal end ( 54 ), a generally curled second end portion ( 57 ) that extends to a second distal end ( 58 ), and a central body portion ( 60 ) between and contiguous with the first and second end portions. The annular seal has a first side ( 70 ) and an opposite second side ( 72 ). The second end portion curls in a first direction ( 73 ) in accordance with a predetermined radius such that the second distal end is located across from the first side of the annular seal and the first and second distal ends do not face each other. The seal can be fabricated from metal or ceramic or alloys.

TECHNICAL FIELD

The present invention generally relates to annular seals.

BACKGROUND ART

In applications wherein it is necessary to contain pressurized fluids,resilient metallic seals are used when elastomeric and polymericmaterials cannot be used because of extremely high pressures, hightemperatures and/or aggressive media. Resilient, metallic seals areproduced in different configurations that are designed to meet a varietyof operating requirements.

One prior art resilient, metallic seal is known as the axial C-seal. TheC-seal, which is available in three basic orientations, was developed asan improvement in flexibility over the hollow metal O-ring. The axialC-seal, which is intended for sealing the space between two concentriccylindrical surfaces, is shown in FIGS. 1A and 1B. As shown incross-section in FIG. 1A, prior art axial C-seal 10 has an arcuateportion 12, outer sealing surface 16 and inner sealing surface 14. Thesefeatures are also shown in FIG. 1B which is an enlarged view of aportion of the view of FIG. 1A. Circumferential lines passing throughthe quadrant points of the section shown in FIG. 1B are known as sealinglines. As with the metal O-ring, the axial C-seal may be used to sealgaps between cylindrical surfaces in mainly static applications.

Other prior art seals have been developed to perform these functionsdescribed above. Some of these seals are disclosed in U.S. Pat. Nos.4,457,523, 4,854,600, 5,799,954, 6,257,594, and 6,446,978. These priorart seals serve their purpose, but they exhibit limitations whenrequired to be pressure-energized and are not capable of accommodatingsignificant lateral misalignments of the cylindrical surfaces to besealed.

Seals, including prior art axial C-seals, are typically used incouplings and other devices that are part of fluid transmission orcontainment systems. In the example of a coupling, a rigid hollowproboscis or probe is typically inserted into a hollow receptacle in thefluid transmission system. The receptacle contains a sealing ring ormultiple sealing rings which are dilated by insertion of the probe. Thisdilation creates the required contact stresses for sealing. The contactstresses achieve fluid containment between the two bodies to be sealedtogether. In some instances, the probe is forced into the receptaclewithout the centerlines or axes of the two components being properlyaligned, as a result of imperfect field installation practices. Whenthis occurs, the probe may displace one side of the axial C-seal to anextent at which the ring may not be sufficiently resilient toelastically deform. A result, a gap may be formed on the opposite sidewhich results in leakage of fluid when the joint is pressurized.

Some prior art seals, when used to seal the joint of two cylindricalsurfaces that are subject to vibrations, have been known to “walk” alongthe cylindrical surfaces. This is the result of the prior art sealsmerely lightly engaging both cylindrical surfaces. The “walking” of theseal results in a back-and-forth movement of the seal which causesexcessive wear of the seal and the cylindrical surfaces it engages.

Another disadvantage of many prior art seals is poor reliability. Thiscauses problems when repeated disengagements and insertions of probesare necessary.

A further disadvantage is that some pressure-energized prior art sealsare extensively plastically deformed at installation and have littleelastic recovery (i.e. springback) from their maximum compressed state,usually less than 3% of their free or uncompressed height.

What is needed is a new and improved seal that overcomes the aforesaiddeficiencies and problems of the prior art seals.

DISCLOSURE OF THE INVENTION

The present invention is directed to a seal for the containment of highor moderate pressure fluids and gases at temperatures ranging fromcryogenic to relatively high levels. The seal has an overall generally“J” shaped or hook-shaped cross-section. Specifically, the seal of thepresent invention is an annular lip seal that has the capability toexhibit superior performance generally and especially when the twoobjects that must be sealed together experience lateral offset, angularmisalignment or axial misalignment.

Thus, in one embodiment, the present invention is directed to an annularseal having a generally “j” shaped cross-section and comprising a firstend portion having a first distal end, a generally curled second endportion that extends to a second distal end, and a central body portionbetween and contiguous with the first and second end portions. Theannular seal has a first side and an opposite second side. The secondend portion curls in a first direction in accordance with apredetermined radius such that the second distal end is located acrossfrom the first side of the annular seal and the first and second distalends do not face each other.

In another embodiment, the present invention is directed to an annularseal comprising a first side and an opposite second side, a generallyfrustro-conical central body portion having opposite ends, a first endportion contiguous with one of the opposite ends of the generallyfrustro-conical central body portion, and a generally curled second endportion contiguous with the other of the opposite ends of the generallyfrustro-conical central body portion. The first end portion has a firstdistal end. The second end portion extends to a second distal end. Thesecond end portion curls in a first direction in accordance with apredetermined radius such that the second distal end is located acrossfrom the first side of the annular seal and the first and second distalends do not face each other.

In another embodiment, the present invention is directed to an annularseal having a generally hook-shaped cross-section, a first side and asecond opposite side. The annular seal comprises a first end portionhaving a first distal end, a generally curled second end portion thatextends to a second distal end, and a central body portion between andcontiguous with the first and second end portions. The second endportion curls in a first direction in accordance with a predeterminedradius such that the second distal end is located across from the firstside of the annular seal and the first and second distal ends do notface each other.

In a further embodiment, the present invention is directed to anannular, metallic seal comprising a first side and an opposite secondside, a generally frustro-conical central body portion having oppositeends, a first end portion contiguous with one of the opposite ends ofthe generally frustro-conical central body portion, and a curled secondend portion contiguous with the other of the opposite ends of thegenerally frustro-conical central body portion. The first end portionhas a first distal end. The second end portion extends to a seconddistal end. The annular seal has a thickness that tapers in thedirection of the first distal end. The first distal end is slightlyangulated in a first direction. The second end portion curls in thefirst direction in accordance with a predetermined radius such that thesecond distal end is located across from the first side of the annular,metallic seal and the first and second distal ends do not face eachother.

Further features and advantages of the present invention will appearherein below.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of the present invention will become more readilyapparent and may be understood by referring to the following detaileddescription of an illustrative embodiment of the present invention,taken in conjunction with the accompanying drawing, in which:

FIG. 1A is a side view, in longitudinal section, of a prior art axialC-seal;

FIG. 1B is an enlarged view of a portion of the view shown in FIG. 1A;

FIG. 2A is plan view of a seal in accordance with one embodiment of thepresent invention;

FIG. 2B is a side view, in longitudinal section, taken along line 2B-2Bof FIG. 2A;

FIG. 2C is an enlarged view of a portion of the view shown in FIG. 2B;

FIG. 2D is a further enlarged cross-sectional view taken along line2D-2D in FIG. 2A;

FIG. 3A is a plan view of a seal in accordance with another embodimentof the present invention.

FIG. 3B is a side view, in longitudinal section, taken along line 3B-3Bof FIG. 3A;

FIG. 3C is a cross-sectional view taken along line 3C-3C of FIG. 3A.

FIG. 4 is a cross-sectional view illustrating the installation of theseal of FIG. 3A in a body of a coupling;

FIG. 5 is a cross-sectional view, based on FIG. 4, showing the seal ofFIG. 3A installed in the body of the coupling with an axis of the probedisplaced to the right;

FIG. 6 is a cross-sectional view, similar to the view of FIG. 5, showingthe axis of the probe displaced to the left;

FIG. 7 is a cross-sectional view of the seal installed in the body ofthe coupling at operating pressure;

FIG. 8A is plan view of a seal in accordance with another embodiment ofthe present invention;

FIG. 8B is a side view, in longitudinal section, taken along line 8B-8Bof FIG. 8A;

FIG. 8C is a cross-sectional view taken along line 8C-8C of FIG. 8A;

FIG. 9A is a plan view of a seal in accordance with a further embodimentof the present invention;

FIG. 9B is a side view, in longitudinal section, taken along line 9B-9Bof FIG. 9A; and

FIG. 9C is a cross-sectional view taken along line 9C-9C of FIG. 9A;

FIG. 10A is a plan view of a seal in accordance with another embodimentof the invention;

FIG. 10B is side view, in longitudinal section, taken along line 10B-10Bof FIG. 10A;

FIG. 11A is a plan view of a seal in accordance with another embodimentof the present invention;

FIG. 11B is a cross-sectional view, in longitudinal section, taken alongline 11B-11B of FIG. 11A;

FIG. 11C is an enlarged view of a portion of the view shown in FIG. 11B;

FIG. 11D is a cross-sectional view of the seal of FIG. 11A installed ina cavity between two components;

FIG. 12A is a plan view of a seal in accordance with a furtherembodiment of the present invention;

FIG. 12B is a cross-sectional view, in longitudinal section, taken alongline 12B-12B of FIG. 12A;

FIG. 12C is an enlarged view of a portion of the view shown in FIG. 12B;

FIG. 12D is a partial, cross-sectional view, illustration theinstallation of the seal of FIG. 12A;

FIGS. 13A and 13B are cross-sectional views illustrating theinstallation of a seal in accordance with another embodiment of thepresent invention;

FIG. 14 is cross-sectional view, similar to FIG. 3C, of a seal inaccordance with another embodiment of the present invention;

FIG. 15 is a cross-sectional view, similar to the view shown in FIG.12C, of a seal in accordance with a further embodiment of the presentinvention; and

FIG. 16 is a cross-sectional view, similar to the view shown in FIG.11C, of a seal in accordance with another embodiment of the presentinvention.

MODES FOR CARRYING OUT THE INVENTION

The ensuing description makes reference to drawings shown as FIGS. 1-16.These figures show various embodiments of the present invention. Thefigures are not drawn to scale.

The seal of the present invention is an axial/radial seal that may beused in low speed, dynamic applications wherein relative axial motionbetween two concentric cylindrical surfaces is caused, for example, bythermal expansion. The seal of the present invention can alsoaccommodate relative radial expansion and some eccentricity and/orangular misalignment of the two cylinders as well as rotationaldisplacements. Specifically, the seal of the present invention combinesa relatively rigid, sealing contact circle, for engagement with one ofthe cylindrical surfaces, and a highly flexible lip seal for slidablyengaging the other cylindrical surface. This particular structure of theseal of the present invention ensures that the seal is restrainedagainst axial and other movement with respect to one cylindrical surfacewhile permitting low-resistance motion of the other cylindrical surface.

Referring to FIGS. 2A, 2B, 2C and 2D, there are shown various views ofseal 50 in accordance with one embodiment of the present invention. Seal50 has a substantially annular shape and has a predetermined degree ofresiliency. Seal 50 has a generally “j” shaped or hook-shapedcross-section. Seal 50 comprises first end portion 52. First end portion52 has a distal end 54. This distal end defines edge 55. Seal 50 furthercomprises a generally curled second end portion 56 that includes anarcuate or curved portion 57. Second end portion 56 extends to distalend 58. Distal end 58 defines edge 59. Seal 50 further comprises centralbody portion 60 that is between and contiguous with first end portion 52and second end portion 56. In a preferred embodiment, central bodyportion 60 has a generally frustro-conical shape. In a preferredembodiment, central body portion 60 is configured so that it does nothave any inflection points formed therein. Seal 50 has first side 70 andopposite second side 72. Second end portion 56 curls in a firstdirection 73 in accordance with a predetermined radius of arcuateportion 57 such that distal end 58 is located across from first side 70by a predetermined distance X1 and distal ends 54 and 58 do not faceeach other. These aforesaid features are also shown in FIG. 2C which isan enlarged view of a portion of the view of FIG. 2B. As shown in FIGS.2A and 2D, seal 50 has outer diameter D1, inner diameter D2, radialwidth W and height H. In this particular embodiment, end portion 52defines inner diameter D2.

Referring to FIG. 2D, in one embodiment, first end portion 52 isslightly angulated in first direction 73 with respect to dashedreference line 90. In one embodiment of the invention, the annular seal50 has a thickness T that tapers in the direction of distal end portion52. In a preferred embodiment, the rate of taper is substantiallyuniform. It has been found that such a taper in thickness increases orenhances the flexibility of seal 50. Preferably, as a result of thetaper, the thickness of seal 50 at first end portion 52 is about 70% ofthe thickness of seal 50 at second end portion 56.

Preferably, end portion 52 has a degree of stiffness that ensuresroundness and stability and which also facilitates engagement with aninner cylindrical surface upon installation. Examples of such an innercylindrical surface would be a piston, rod or shaft. The relativelysmall size and stiffness of end portion 52 avoids an increase in theinstallation and sliding forces. Furthermore, the relatively small sizeof end portion 52 reduces the second moment of area at the end of seal50 and thus, reduces the seal's resistance to deflection at that end.Preferably, end portion 56 has a relatively high degree of stiffness sothat when seal 50 is installed, end portion 56 clings tightly to theouter cylindrical surface of the sealing cavity thereby resisting axialforces from the slidable end of seal 50. The result is a leak-tightseal. An example of such an outer cylindrical cavity surface would bethe inner surface of a bore, tube or hole.

The size of seal 50 can be varied in order to be used in variousapplications. For example, in one embodiment, outer diameter D1 is about78.18 mm, inner diameter D2 is about 70.76 mm, radial width W is about3.7 mm and height H is about 5.84 mm. It is to be understood that seal50 can be configured to have other dimensions. The actual dimensionsdepend upon the particular application with which the seal will be used.

Referring to FIGS. 3A, 3B and 3C, there is shown seal 100 in accordancewith an alternate embodiment of the invention. In this embodiment, thethickness of seal 100 does not taper. Seal 100 has a generally “j”shaped or hook-shaped cross-section and comprises first end portion 102.First end portion 102 has a distal end 104. Distal end 104 defines edge105. Seal 100 further comprises a generally curled second end portion106 that has curved or arcuate portion 107. Curled second end portion106 extends to distal end 108. Distal end 108 defines edge 110. Seal 100further comprises central body portion 120 that is between andcontiguous with first end portion 102 and second end portion 106.Preferably, central body portion 120 has a generally frustro-conicalshape. Seal 100 has first side 130 and opposite second side 132. Asshown in FIG. 3C, second end portion 106 curls in a first direction 140in accordance with a predetermined radius of arcuate portion 107 suchthat distal end 108 is located across from first side 130 by apredetermined distance X2 and distal ends 104 and 108 do not face eachother. In accordance with this embodiment of the invention, thethickness of seal 100 does not have a taper and the thickness of seal100 is uniform throughout.

Referring to FIG. 4, there is illustrated the installation of a seal ofthe present invention in the body of a coupling. For purposes ofexample, seal 100 is shown inserted into body 200 of a coupling. Axialretaining wall 202 is positioned adjacent seal 100 and probe 204 isspaced apart from seal 100. The center-line of probe 204 is indicated byreference number 206. Referring to FIG. 5, seal 100 is installed in aninterference relationship with body 200 and abuts axial retaining wall202 while probe 204 is inserted in contacting, interfering relationshipwith seal 100. Probe 204 contacts frustro-conical portion 120 of seal100. End portion 102 and frustro-conical central body portion 120elastically deflect so as to allow lateral offset of probe 204 in thedirection indicated by arrow 208 without causing leakage. Thus,center-line 206 of probe 204 is displaced to the right with respect tobody 200. Sealing contact is maintained by virtue of hoop stress,keeping all points around the inner circumference of the seal in tightcontact with the probe. Referring to FIG. 6, center-line 206 of probe204 is now displaced to the left with respect to body 200, in thedirection indicated by arrow 210, thereby widening the space or gap 212between central body portion 120 of seal 100 and body 200.

Referring to FIG. 7, there is shown a view similar to the views shown inFIGS. 5 and 6 showing seal 100 installed in body 200 of a coupling. Whenseal 100 is operated at relatively high pressures, such as 30,000 psi,relatively high-stress contact regions are formed on probe 204,retaining wall 202 and body 200. These high-stress contact regions areindicated by reference numbers 250. High contact stresses are needed toprevent leakage of high pressure fluids.

As described in the foregoing description, seal 100 does not have atapered thickness as does seal 50. If seal 50 was installed in the bodyof the coupling as shown in FIGS. 4-7 instead of seal 100, the taperedthickness would allow an increase in the lateral offset of probe 204.

Referring to FIGS. 8A, 8B and 8C, there is shown seal 300 in accordancewith another embodiment of the invention. Seal 300 has a substantiallyannular shape and a predetermined degree of resiliency. Seal 300 has agenerally “j” shaped or hook-shaped cross-section. Seal 300 comprisesfirst end portion 302. First end portion 302 has a distal end 304.Distal end 304 defines edge 305. Seal 300 further comprises a generallycurled second end portion 306. Second end portion 306 includes arcuateor curved portion 307. Second end portion 306 extends to distal end 308.Distal end 308 defines edge 309 (see FIG. 8C) Seal 300 further comprisescentral body portion 310 that is between and contiguous with first endportion 302 and second end portion 306. In a preferred embodiment,central body portion 310 has a generally frustro-conical shape. In apreferred embodiment, central body portion 310 is configured so that ithas neither a taper in material thickness nor any inflection pointsformed therein. Seal 300 has first side 370 and opposite second side372. Second end portion 306 curls in a direction indicated by arrow 373in accordance with a predetermined radius of arcuate portion 307 suchthat distal end 308 is located across from first side 370 by apredetermined distance X3 and distal ends 304 and 308 do not face eachother. Seal 300 has outer diameter D1, inner diameter D2, radial width Wand height H. In accordance with this embodiment of the invention, firstend portion 302 defines outer diameter D1.

Referring to FIG. 8C, in one embodiment, first end portion 302 isslightly angulated in first direction 373 with respect to dashedreference line 390. In this embodiment, the material thickness of seal300 is substantially uniform and there is no taper in the materialthickness.

Test Results

The seal of the present invention conforming to FIGS. 8A-8C was testedin order to evaluate operating characteristics. The seal tested had anoutside diameter D1 of about 80 mm, a radial width W of about 3.7 mm anda material thickness T of about 0.25 mm. The seal was inserted betweentwo coaxial cylindrical components. The test apparatus was firstpressurized with air at 700 Kpa (kilopascals). The measured initialleakage was 0.0023 l/s (liters/second) without any offset applied to thecylindrical components. Next, a lateral offset was applied to thecylindrical components. The lateral offset was introduced in stages andwas increased to about 0.30 mm without any increase in leakage. When thelateral offset was increased to 0.35 mm, the leakage increased toapproximately 0.017 l/s (liters/second).

In contrast to the performance of the seal of the present invention, asshown by the foregoing test, a typical prior art axial C-seal having anoutside diameter of about 80 mm reaches its limit for sealing efficacywhen an offset between about 0.025 to 0.050 mm is applied to the coaxialcylindrical components.

In another test, a small seal of the configuration shown in FIGS. 3A-3Dwas tested in order to evaluate sealing efficacy with respect to oil.The seal had an outside diameter D1 of about 19.13 mm, a radial width Wof about 1.68 mm and a material thickness T of about 0.25 mm. The sealwas able to seal oil at 40,000 psi and was reusable following multiple“stabbing” connections. This small diameter seal demonstrated sealingefficacy up to a 0.05 mm offset applied to the cylindrical components.

Referring to FIGS. 9A, 9B and 9C, there is shown seal 500 in accordancewith another embodiment of the present invention. Seal 500 has asubstantially annular shape and a predetermined degree of resiliency.Seal 500 has an outer diameter D1, an inner diameter D2, a radial widthW and a height H (see FIG. 9C). The radial width W spans the tangencypoints. Seal 500 has a generally hook-shaped cross-section. Seal 500comprises first end portion 502. First end portion 502 has a distal end504. Distal end 504 defines edge 505. Seal 500 further comprises agenerally curled second end portion 506. Second end portion 506 includesarcuate or curved portion 507A. Second end portion 506 includes portion507B which extends to distal end 508. Second end portion 506 alsoincludes a linear portion 507C that is between and contiguous withportions 507A and 507B. The purpose of linear portion 507C is discussedin the ensuing description. Distal end 508 defines edge 509. Seal 500further comprises central body portion 510 that is between andcontiguous with first end portion 502 and second end portion 506. In apreferred embodiment, central body portion 510 has a generallyfrustro-conical shape. Central body portion 510 is configured so that itdoes not have any inflection points formed therein. Seal 500 has firstside 520 and opposite second side 522. In accordance with thisembodiment of the invention, second end portion 506 curls in a directionindicated by arrow 530 in accordance with a predetermined radius ofarcuate or curved portion 507A such that distal end 508 is locatedacross from first side 520 by a predetermined distance X4. As a resultof this configuration, distal ends 504 and 508 do not face each other.In this embodiment, end portion 502 defines inside diameter D2.

Referring to FIG. 9C, in one embodiment, first end portion 502 isslightly angulated in first direction 530 with respect to dashedreference line 610. Portion 507B of second end portion 506 slightlycurls inward. However, distal ends 504 and 508 do not directly face eachother. In one embodiment, seal 500 has a uniform thickness. In analternate embodiment, seal 500 has a thickness that tapers in thedirection of end portion 502. The length of generally linear portion507C and the radius of arcuate portion 507A determine the distance X4which separates distal end 508 from side 520 of central body portion510. Thus, increasing the radius of arcuate portion 507A and the lengthof generally linear portion 507C will increase distance X4. Likewise,decreasing the radius of arcuate portion 507A and the length of linearportion 507C decreases the distance X4. Such a configuration allows seal500 to be retrofitted to existing cavities that were originally designedfor a different type of seal. Seal 500 has generally the same operatingcharacteristics as the other embodiments of the seal of the presentinvention described in the foregoing description.

Referring to FIGS. 10A and 10B, there is shown seal 600 in accordancewith another embodiment of the present invention. Seal 600, like seal500, is configured to be retrofitted to existing cavities that wereoriginally designed for a different type of seal. As will be apparentfrom the ensuing description, the configuration of seal 600 is oppositeto the configuration of seal 500. Seal 600 has a substantially annularshape and a predetermined degree of resiliency. Seal 600 has a generallyhook-shaped cross-section. Seal 600 comprises first end portion 602.First end portion 602 has a distal end 604. This distal end 604 definesedge 605. Seal 600 further comprises a generally curled second endportion 606. Second end portion 606 includes arcuate or curved portion607A. Second end portion 606 includes portion 607B which extends todistal end 608. Distal end portion 608 has edge 609. Second end portion606 also includes a linear portion 607C that is between and contiguouswith portions 607A and 607B. The purpose of linear portion 607C is thesame as linear portion 507C of seal 500 discussed in the foregoingdescription. Seal 600 further comprises central body portion 610 that isbetween and contiguous with first end portion 602 and second end portion606. In a preferred embodiment, central body portion 610 has a generallyfrustro-conical shape. Seal 600 has first side 640 and an oppositesecond side (not shown). In accordance with this embodiment of theinvention, second end portion 606 curls in a direction in accordancewith a predetermined radius of arcuate or curved portion 607A such thatdistal end 608 is located across from first side 640 by a predetermineddistance. Portion 607B of end portion 606 is slightly angulated inwardas is portion 507B of seal 500. Distal ends 604 and 608 do not directlyface each other. In accordance with this embodiment, end portion 602defines the outer diameter D1 of seal 600. In one embodiment, thematerial thickness of the seal 600 is substantially uniform. In analternate embodiment, seal 600 has a thickness that tapers in thedirection of end portion 602.

Referring to FIG. 10B, the length of generally linear portion 607C andthe radius of arcuate portion 607A determine the distance whichseparates distal end 608 from side 640. Thus, increasing the radius ofarcuate portion 607A and the length of generally linear portion 607Cwill increase the distance between side 640 and distal end 608.Decreasing the radius of arcuate portion 607A and the length of linearportion 607C decreases the distance between side 640 and distal end 608.

Referring to FIGS. 11A, 11B and 11C, there are shown various views of aninternal pressure face seal 700 in accordance with a further embodimentof the invention. FIG. 11C is an enlarged view of a portion of the viewof FIG. 11B. A comparison of external pressure face seal 700 (as shownin FIG. 11C) to seal 300 of FIG. 8C shows that the configuration of seal700 is based upon a rotation of seal 300 in a counter-clockwiseorientation. The degree of rotation is about 90 degrees. Seal 700 has asubstantially annular shape and has predetermined degree of resiliency.Seal 700 has a generally “j” shaped or hook-shaped cross-section. Seal700 comprises first end portion 702. First end portion 702 has a distalend 704. Distal end defines edge 705 (see FIG. 11C). Seal 700 furthercomprises a generally curled second end portion 706 that includes anarcuate or curved portion 707. Second end portion 706 extends to distalend 708. Distal end 708 defines edge 709. Seal 700 further comprisescentral body portion 710 that is between and contiguous with first endportion 702 and second end portion 706. In a preferred embodiment,central body portion 710 is configured so that it does not have anyinflection points formed therein. Seal 700 has first side 720 andopposite second side 722 (see FIG. 11A). Second end portion 706 curls ina first direction 730 in accordance with a predetermined radius ofarcuate portion 707 such that distal end 708 is located across fromfirst side 720 by a predetermined distance and distal ends 704 and 708do not face each other. As shown in FIG. 11A, seal 700 has outerdiameter D1 and inner diameter D2. In this particular embodiment, endportion 702 defines inner diameter D2. In accordance with thisembodiment of the invention, seal 700 is configured so that when theseal 700 is positioned as shown in FIG. 11A, central body portion 710 isnot upstanding or vertical, but rather, is in a somewhat generallyhorizontal position as shown in FIG. 11C.

Referring to FIG. 11C, in one embodiment, first end portion 702 isslightly angulated in first direction 730. In one embodiment, seal 700has a thickness that is uniform. In an alternate embodiment, seal 700 isconfigured to have a thickness that tapers in the direction of distalend portion 702.

Referring to FIG. 11D, there is shown internal pressure face seal 700installed between two components. Component 780 has groove 782 withinwhich seal 700 is positioned. Component 780 includes wall portion 784and inner surface 785. Inner surface 785 tangentially contacts endportion 706 of seal 700. Wall portion 784 is a flow-improvement featurewhich may or may not be present. Component 790 is above component 780and has inner surface 792. Inner surface 792 contacts seal 700tangentially at end portion 702. The advantages of seal 700 arediscussed in the ensuing description.

Referring to FIGS. 12A, 12B and 12C, there are shown various views of anexternal pressure face seal 800 in accordance with a further embodimentof the invention. FIG. 12C is an enlarged view of a portion of the viewof FIG. 12B. A comparison of external pressure face seal 800 (as shownin FIG. 12C) to seal 300 of FIG. 8C shows that the configuration of seal800 is based on rotation of seal section 300 in a clock-wise direction.Preferably, the degree of rotation is about 90 degrees. Seal 800 has asubstantially annular shape and has predetermined degree of resiliency.Seal 800 has a generally “j” shaped or hook-shaped cross-section. Seal800 comprises first end portion 802. First end portion 802 has a distalend 804. This distal end 804 defines edge 805. Seal 800 furthercomprises a generally curled second end portion 806 that includes anarcuate or curved portion 807. Second end portion 806 extends to distalend 808. Distal end 808 defines edge 809. Seal 800 further comprisescentral body portion 810 that is between and contiguous with first endportion 802 and second end portion 806. In a preferred embodiment,central body portion 810 is configured so that it does not have anyinflection points formed therein. Seal 800 has first side 820 andopposite second side 822. Second end portion 806 curls in a firstdirection 830 in accordance with a predetermined radius of arcuateportion 807 such that distal end 808 is located across from first side820 by a predetermined distance and distal ends 804 and 808 do not faceeach other. As shown in FIG. 12A, seal 800 has outer diameter D1 andinner diameter D2. In this particular embodiment, end portion 802defines outer diameter D1. In accordance with this embodiment of theinvention, seal 800 is configured so that when the seal 800 ispositioned as shown in FIG. 12A, central body portion 810 is notupstanding or vertical, but rather, is in a somewhat general horizontalposition.

Referring to FIG. 12C, in one embodiment, first end portion 802 isslightly angulated in first direction 830. In one embodiment, seal 800has a thickness that is uniform. In an alternate embodiment, seal 800 isconfigured to have a thickness that tapers in the direction of distalend portion 802.

Referring to FIG. 12D, there is shown external pressure face seal 800installed between two components that are in a confronting relationship.Component 880 has cavity or channel 882 within which external pressureface seal 800 is positioned. Component 880 includes wall portion 884 andinner surface 885. Inner surface 885 tangentially contacts a portion ofend 806 of seal 800. Component 890 is above component 880 and has innersurface 892 that tangentially contacts seal 800 at end portion 802.

Due to the configuration of seals 700 and 800, these seals do notundergo extensive plastic deformation. An important feature andadvantage of seal 700 and seal 800 is that these seals are capable ofelastic recovery of over 8% of their uncompressed height, even afteroperating at high pressures and temperatures. A characteristic of seals700 and 800 is that when either of these seals has a relatively smalldiameter, they deflect relatively more in flexure of theircross-sections than in torsion. In contrast, seals having a relativelylarge diameter-to-cross-section ratio accommodate more of the inputdeflection in torsion.

The seals of the present invention may be installed between surfacesthat form various geometrical shapes. For example, in FIGS. 13A and 13B,there is shown seal 900 that is installed between components 901 and902. Components 901 and 902 have generally conical surfaces. FIG. 13Ashows seal 900 just prior to complete installation and FIG. 13B showsseal 900 after it is completely installed. The structure of seal 900 isbasically the structure of seal 300 with the cross-section of seal 300rotated forty-five (45) degrees. Referring to FIG. 13A, component 901has extending conical surface 904 and component 902 has extendingconical surface 906. A portion of seal 900, indicated by referencenumber 994, abuts surface 904. Another portion of seal 900, indicated byreference number 996, abuts surface 906.

The seal of the present invention may be fabricated from a variety ofmaterials. In a preferred embodiment, the seal of the present inventionis fabricated from a ductile, corrosion resistant, high strength metal.In certain cases, the metal must be suitable for continuous use at 1300degrees F. Suitable metals for fabricating the seal of the presentinvention include nickel based alloys, nickel super alloys,nickel-cobalt alloys, copper based alloys, aluminum-based alloys andstainless steel. Other suitable metals and alloys include aprecipitation hardened, high-temperature alloy such as Waspaloy orInconel. One such suitable nickel alloy is Nickel Alloy 718 which hasbeen found to have excellent properties at both low and elevatedtemperatures.

Coatings may be applied to the sliding contact surfaces of the seal toenhance sealing efficiency and/or reduce wear.

In another embodiment, the seal of the present invention is fabricatedfrom composite materials. In a further embodiment, the seal of thepresent invention is fabricated from a ceramic material.

As described in the foregoing description, the seal of the presentinvention, when used between two concentric cylindrical surfaces, isretained in position on one or more of the two cylindrical surfaces byinterference fit between the cylindrical diameter and the relativelystiff annular portion of the seal. The other annular portion of theseal, either the external or internal annular portion, is designed to bemore flexible and exerts a relatively light interference force againstthe co-operating cylindrical surface. This enables sliding motion totake place at the co-operating cylindrical surface, while ensuring fluidcontainment at that location. For example, when the seal of the presentinvention is used to eliminate excessive leakage from a sectionalexhaust manifold assembly, existing slip joints are modified to providean annular sealing cavity. The seal is mounted on the inner cylindricalsurface and slidingly engages the outer cylindrical surface with themore resilient leg of the seal's “J” shaped cross-section or hook-shapedcross-section so as to accommodate axial and radial thermal expansionmovements.

Since the seal is retained to one cylindrical surface, the seal does not“walk” along the cylindrical surfaces when vibrations are present as domany prior art seals that merely lightly engage both cylindricalsurfaces. In contrast, the seal of the present invention is displaced adistance that is solely due to the design conditions involvingmechanical movements, thermal excursions, etc.

Thus, the present invention provides a resilient seal for high-pressuresystems and connectors. There are many applications in which the seal ofthe present invention may be used. One such application is to provideimproved sealing in exhaust-gas containment and recirculation ductingsystems for modern, ecologically superior, highly efficient diesel truckengines.

It is preferred that prior to the installation of the seal of thepresent invention between two generally coaxial cylindrical surfaces asdescribed in the foregoing description, lubricating oils may be appliedto the cylindrical surfaces of the sealing cavities to facilitateassembly. Tribological coatings may be applied to the seal of thepresent invention to reduce wear. Other coatings, such as silver orgold, may be beneficially applied to the seal or its contact surfaces inorder to improve its sealing efficiency. For dynamic applications, soft,lubricious or anti-galling, low-friction coatings may be applied to theseal's contact surfaces.

Thus, the seal of the present invention has several significantadvantages. Referring to FIGS. 2A-2C, one advantage is the flexibilityof second end portion 56 which allows said second end portion to bedeflected radially by a lower force. Another advantage is that centralbody portion 60 deflects easily and thus may be deflected to accommodatean off-center probe without plastic deformation of this region. The sealof the present invention may be fabricated from material that isrelatively thicker than the material used to fabricate prior art axialC-seal without an appreciable increase in insertion force or gallingtendencies. When the seal of the present invention is made with suchrelatively thicker material, the greater material thickness and a closeproximity between the installed probe and the deflected central bodyportion of the seal allow the seal to withstand the application ofhigher operating pressures without significant permanent deformation.

The seal of the present invention exhibits a high degree of reliabilityin accommodating multiple insertions of a probe. The frustro-conicalgeometry of the seal's central body portion is advantageous for dynamic,sliding applications, albeit at slow speeds, because of reduction ofcontact stresses.

Although particular seal configurations and shapes have been describedin the foregoing description, other configurations and shapes arepossible. For example, the central body portion can be configured tohave a generally conical shape or a slight curve. For example, referringto FIGS. 14, 15 and 16, there are shown alternate embodiments of theseals of the present invention wherein each seal is configured to have acurvature. FIG. 14 shows a cross-sectional view, similar to the view ofFIG. 3C, of a seal in accordance with an alternate embodiment of presentinvention. Seal 100′ is generally the same as seal 100 of FIG. 3A exceptthat seal 100′ has a curvature. Seal 100′ has a generally “j” shaped orhook-shaped cross-section and comprises first end portion 102′. Firstend portion 102′ has a distal end 104′. Distal end 104′ defines edge105′. Seal 100′ further comprises a generally curled second end portion106′ that has curved or arcuate portion 107′. Curled second end portion106′ extends to distal end 108′. Distal end 108′ defines edge 110′. Seal100′ further comprises central body portion 120′ that is between andcontiguous with first end portion 102′ and second end portion 106′.Preferably, central body portion 120′ has a generally frustro-conicalshape. In accordance with this embodiment of the invention, central bodyportion 120′ has a curvature or a “curving” geometry generally indicatedby reference number 1000. Seal 100′ has first side 130′ and oppositesecond side 132′. Second end portion 106′ curls in a first direction inaccordance with a predetermined radius of arcuate portion 107′ such thatdistal end 108′ is located across from first side 130′ and distal ends104′ and 108′ do not face each other. In accordance with this embodimentof the invention, the material thickness of seal 100′ is uniformthroughout. In an alternate embodiment, the material thickness of seal100′ is tapered.

Referring to FIG. 15, there is shown seal 800′ which is an alternateembodiment of seal 800 of FIGS. 12A, 12B and 12C. Seal 800′ hasgenerally the same construction as seal 800 except that seal 800′ has acurvature. The view shown in FIG. 15 is similar to the cross-sectionalview shown in FIG. 12C. Seal 800′ has a generally “j” shaped orhook-shaped cross-section. Seal 800′ comprises first end portion 802′.First end portion 802′ has a distal end 804′. This distal end definesedge 805′. Seal 800′ further comprises a generally curled second endportion 806′ that includes an arcuate or curved portion 807′. Second endportion 806′ extends to distal end 808′. Distal end 808′ defines edge809′. Seal 800′ further comprises central body portion 810′ that isbetween and contiguous with first end portion 802′ and second endportion 806′. In accordance with this embodiment of the invention,central body portion 810′ is configured so that it has a curvature or“curving” geometry generally indicated by reference number 1100. Seal800′ has first side 820′ and opposite second side 822′. Second endportion 806′ curls in a first direction 830′ in accordance with apredetermined radius of arcuate portion 807′ such that distal end 808′is located across from first side 820′ by a predetermined distance anddistal ends 804′ and 808′ do not face each other.

Referring to FIG. 16, there is shown seal 700′ which is an alternateembodiment of seal 700 shown in FIGS. 11A, 11B and 11C. The view shownin FIG. 16 is a cross-sectional view that is similar to the view shownin FIG. 11C. Seal 700′ has generally the same structure as seal 700except seal 700′ has a curvature. Seal 700′ has a generally “j” shapedor hook-shaped cross-section. Seal 700′ comprises first end portion702′. First end portion 702′ has a distal end 704′. Distal end definesedge 705′. Seal 700′ further comprises a generally curled second endportion 706′ that includes an arcuate or curved portion 707′. Second endportion 706′ extends to distal end 708′. Distal end 708′ defines edge709′. Seal 700′ further comprises central body portion 710′ that isbetween and contiguous with first end portion 702′ and second endportion 706′. In accordance with this embodiment, central body portion710′ is configured so that it has a curvature or a “curving” geometrygenerally indicated by reference number 1200. Seal 700′ has first side720′ and an opposite second side (not shown). Second end portion 706′curls in a first direction 730′ in accordance with a predeterminedradius of arcuate portion 707′ such that distal end 708′ is locatedacross from first side 720′ by a predetermined distance and distal ends704′ and 708′ do not face each other.

The material thickness of the seals can be varied at different locationson the seal and do not have to be uniform. Other modifications arepossible.

The principles, preferred embodiments and modes of operation of thepresent invention have been described in the foregoing specification.The invention which is intended to be protected herein should not,however, be construed as limited to the particular forms disclosed, asthese are to be regarded as illustrative rather than restrictive. Thus,it is to be understood that the invention is not limited to theillustrations described and shown herein, which are deemed to be merelyillustrative of the best modes of carrying out the invention, and whichare susceptible of modification of form, size, and arrangement of partsand details of operation. The invention is intended to encompass allsuch modifications which are within the spirit and scope as defined bythe attached claims.

1. An annular seal having a generally hook shaped cross-section andcomprising a first end portion having a first distal end, a generallycurled second end portion that extends to a second distal end, and acentral body portion between and contiguous with said first and secondend portions, said central body portion having a slight curve, saidannular seal having a first side and an opposite second side, saidsecond end portion curling in a first direction in accordance with apredetermined radius such that said second distal end is located acrossfrom said first side of said annular seal and said first and seconddistal ends do not face each other.
 2. The annular seal according toclaim 1 wherein the portion of the first end portion having said firstdistal end is slightly angulated.
 3. The annular seal according to claim1 wherein said central body portion has a generally frustro-conicalshape.
 4. The annular seal according to claim 1 wherein said centralbody portion is configured without inflection points.
 5. The annularseal according to claim 1 wherein said annular seal has a degree ofresiliency.
 6. The annular seal according to claim 1 wherein saidannular seal has a thickness that tapers toward said first distal end.7. The annular seal according to claim 1 wherein said second end portioncomprises an arcuate portion having said predetermined radius and agenerally linear section extending between said arcuate portion and saidsecond distal end.
 8. The annular seal according to claim 7 wherein saidsecond end portion includes a distal portion that has said second distalend, said distal portion being slightly angulated in a direction that isopposite said first direction.
 9. The annular seal according to claim 1wherein said annular seal is metallic.
 10. The annular seal according toclaim 1 wherein said annular seal is fabricated from an alloy chosenfrom the group consisting of nickel-based alloys, nickel super alloys,nickel cobalt alloys, copper-based alloys, aluminum-based alloys,Waspaloy and Inconel.
 11. The annular seal according to claim 1 whereinsaid annular seal is fabricated from a composite material.
 12. Theannular seal according to claim 1 wherein said annular seal isfabricated from a ceramic material. 13-24. (canceled)
 25. The annularseal according to claim 6 wherein the rate of taper is such that thethickness of said annular seal at said first end portion is about 70% ofthe thickness of said annular seal at said second end portion. 26-31.(canceled)
 32. An annular, axial seal comprising: a central sectionhaving of opposite ends, a first side and an opposite second side, saidcentral section having a slight curve; a curled section contiguous withone of said ends of said central section, said curled section curling ina first direction to a distal end, said curled section curling in saidfirst direction in accordance with a predetermined radius andpredetermined distance such that said distal end of said curled sectionis located directly across from said first side of said central section;said central section and said curled section providing a generally hookshaped cross-section; and a slightly curved tip portion contiguous withthe opposite end of said central section such that said central sectionis between said slightly curved tip portion and said curled section,said slightly curved tip portion having an end that does not directlyface said distal end of said curled section.